If you see a opossum leave them alone, they mean no harm. Some facts about the Opossum:
Opossums are resistant to rabies
They avoid trouble and aren’t aggressive.
The first defensee reaction is showing off their teeth while hissing. If that doesn’t work, they play dead.
They eat ticks and don’t carry Lyme disease.
They also help out by eating insects, snails, small rodents and dead stuff.
They are North America’s only marsupial.